ASUS Xonar Essence One DAC and amplifier

Audio enthusiasts are becoming more and more particular about their sources, pouring a ton of money into everything from high-end CD players and vinyl players to headphone amplifiers and dedicated DACs. These are somewhat difficult to find locally and there’s been some stagnation in the PC audio source market. From some time now, ASUS has been the only active brand selling sound cards designed specifically for desktops. The last major release that caught our attention was the Essence STX. They’ve got us salivating again and this time it’s because of the over-the-top, headphone external DAC-amplifier ASUS is calling the Xonar Essence One.

Design and Build Quality

If the Xonar Essence One were a tank, it would undoubtedly be the M1 Abrams. It’s by far the heaviest audio source for a headphone that we’ve seen. It weighs more than a high-end gaming laptop does and is built inside a solid metal frame. This is not a DAC you’re going to be carrying around with you everywhere you go. 

All the connectivity options you'll need

The Essence One has a whole bunch of controls at the front. The dials and knobs are made of plastic. The primary volume dials are larger, but we would’ve preferred chrome metal dials in place of plastic ones.

The insides of the beast

Still, the dials have a very nice feel and grip to them. The bundled connector and cables are of good quality, as well. The power supply is built into the chassis of the DAC.

Features

At the heart of the Essence One is the C-Media CM6631 sound processor. It’s the same chip used in some other high-end enthusiast level full-scale speaker amplifiers and receivers. The CM6631 enables the Essence One to support upto 192kHz sample rates at 16/24-bit lengths. The Xonar Essence One comes in a huge box bundled with the necessary cables, a certificate with test results, a manual and an installation disc. The USB cable is used to connect your PC or notebook to the DAC. 

Connectivity options include the USB port, a TOSlink optical port, a balanced pair of XLR ports for output, a 6.3mm analog port for the headphones at the front. A gold plated 6.3mm to 3.5mm connector is also bundled. SPDIF inputs are also present. The Essence One has ASIO support and we also used WASAPI while reviewing the product. The amplifier is able to drive 600 Ohm impedance headphones. There is no microphone input.

The dials at the front of the player let you select the source, set the volume and mute the source. There are a line of indicators that tell you the sample rate of the audio signal, as well. There are two volume dials, one for the headphone connector at the front and the other for speakers if you use the output connections at the rear.

Op-amp that can be swapped

Open it up and you’re treated to a very neatly packed PCB with the large power transformer and a separate board that handles all of the power requirements of the Essence One. The C-Media CMI6631 chip is hidden under a heatsink. There’s also an Analog Devices ADSP-21261 signal processor that's clearly visible. 

Analog Devices signal processor

There’s a set of Texas Instruments NE5532P op-amps being used, as well as a few LM4562NA op-amps from National Semiconductors. ASUS claims you can swap these with others to change the way the DAC sounds.